Python的datetime常用幾個操作

''''' 日期相關的操作 '''

from datetime import datetime

from datetime import timedelta
DATE_FMT = '%Y-%m-%d'

DATETIME_FMT = '%Y-%m-%d %H:%M:%S'

DATE_US_FMT = '%d/%m/%Y'
''''' 
格式化常用的幾個參數 
Y ： 1999 
y ：99 
m : mouth 02 12

M : minute 00-59 
S : second 
d : day 
H : hour 
'''
def dateToStr(date):

    '''''把datetime類型的時間格式化自己想要的格式'''

    return datetime.strftime(date, DATETIME_FMT)
def strToDate(strdate):

    '''''把str變成日期用來做一些操作'''

    return datetime.strptime(strdate, DATETIME_FMT)
def timeElement():

    '''''獲取一個時間對象的各個元素'''

    now = datetime.today()

    print 'year: %s  month: %s  day: %s' %(now.year, now.month, now.day)

    print 'hour: %s  minute: %s  second: %s' %(now.hour, now.minute, now.second)

    print 'weekday: %s ' %(now.weekday()+1)  #一周是從0開始的
def timeAdd():

    ''''' 
    時間的加減，前一天后一天等操作

    datetime.timedelta([days[, seconds[, microseconds[, milliseconds[, minutes[, hours[, weeks]]]]]]])

    參數可以是正數也可以是負數

    得到的對象可以加也可以減 乘以數字和求絕對值 
    '''

    atime = timedelta(days=-1)

    now = datetime.strptime('2001-01-30 11:01:02', DATETIME_FMT)

    print now + atime

    print now - abs(atime)

    print now - abs(atime)*31
import calendar

def lastFirday():

     today = datetime.today()

     targetDay = calendar.FRIDAY

     thisDay = today.weekday()

     de = (thisDay - targetDay) % 7

     res = today - timedelta(days=de)

     print res
def test():

#print dateToStr(datetime.today())  
#print strToDate('2013-01-31 12:00:01')  
#timeElement()  
#timeAdd()  
#lastFirday()  



if name=='main':

    test()  </pre>